In the prior art, there are well-known heat exchangers that are provided with a plurality of flat tubes, fins that are joined to the plurality of flat tubes, and header collecting tubes respectively connected to a first end side and another end side of the plurality of flat tubes. In these heat exchangers, heat is exchanged between refrigerant flowing through the interior of the flat tubes and air passing the exterior of the flat tubes.
For example, in the heat exchanger disclosed in Japanese Laid-open Patent Publication No. H02-219966, a configuration is adopted in which both ends of a plurality of outflow tubes that extend in a horizontal direction are respectively connected to header collecting tubes that extend in a vertical direction.
The heat exchanger disclosed in Japanese Laid-open Patent Publication No. H02-219966 addresses the problem that, within the header collecting tubes that extend in the vertical direction, liquid phase refrigerant having a high specific gravity collects at the lower part and gas phase refrigerant having a low specific gravity collects at the upper part, whereby an unevenly distributed flow is generated. In order to solve this problem, a configuration is proposed in which a throttle is formed within the header collecting tubes.
Passing the refrigerant through the throttle formed in this manner facilitates mixing of the gas phase refrigerant and the liquid phase refrigerant, while at the same time increases the flow rate, making it easy for the refrigerant to be caused to reach the upper part within the header collecting tubes, thereby minimizing unevenly distributed flow of the refrigerant.